I expect they’re killing two birds with one stone. It’s actually via Northallerton and Middlesbrough.
As well as the usual Newcastle to Northallerton route learning for diversions, they also expect to run to Middlesbrough before long. So depending on what stabling, reversing or other ECS moves are required between timetabled Middlesbrough trains then they probably need to learn a fair number of alternative moves in the area. Wilton FLT might just be a convenient reversing location en route.
But here’s the two services on RTT for today, if anyone wants to add their thoughts:
Train information at Wilton F.L.T. between 0600 and 2000 on 25/03/2021. From Realtime Trains, an independent source of train running info for Great Britain.
www.realtimetrains.co.uk